This
slide is an example of some of the amazing complexity that is evident
in the photographs of the rings. At the upper right is the outer edge
of the ring system close to a narrow division in the rings (the Encke
Gap). The curved group of gaps and faint material near the bottom is the
Cassini division; in this exposure it is evident that the division is
not empty but merely less completely filled with material than the rest
of the rings. The dense portions of the rings appear very bright because
they are overexposed in this particular photograph. The black “dots”
are reference marks for image processing. Precise measurements of the
light of a star as it passed behind the rings, as seen from the Voyager 1
spacecraft, revealed that as many as 10,000 concentrations of material
may exist within the entire ring system. Other measurements made by the
spacecraft indicate that the rings consist of particles of water ice ranging
in size from tens of centimeters (about 1 foot) to 5 meters
(about 16 feet).